As the castles crumble, does it really matter if UMG merges with EMI, anyway? YES, according to groups like Impala and now the Future of Music Coalition, which are actively lobbying on both sides of the Atlantic against the tie-up. Meanwhile, the labels have formally submitted their request to the European Commission, which pegged March 23rd as an approval date. US submissions happened two months ago, according to details shared by Impala…